Water-borne coating compositions are intensively studied in this field, because they are very useful in view of avoiding fire risk and avoiding use of an organic solvent which is expensive and harmful.
Japanese Patent Publication (examined) No. 58101/1986 discloses a water dispersed coating composition which contains an acrylic graft copolymer. The acrylic graft copolymer has an acid value of 15 to 40 and a glass transition temperature of -10.degree. to 70.degree. C. It also has carboxyl groups, hydroxyl groups and optionally amide groups. The composition, however, is still poor in coating workability and circulation stability.